Mobile terminals such as a mobile phone and a smartphone fundamentally perform a voice communication function using wireless networks provided by mobile service providers. However, recently such devices additionally provide a messenger function for transmitting and receiving messages through wireless networks as well as a multimedia function for playing back media files or capturing images with a camera. Since a user carries the mobile terminal to perform voice communication or video communication, the size of the mobile terminal is required to be small and thin. In order to satisfy such requirements, the size of a touch screen, which is mainly used as an input device for the mobile terminal, is limited to a size of several inches.
Accordingly, in order to satisfy contradictory conditions that the size remains small and thin while user convenience is enhanced, the menu structure of a mobile terminal has developed differently than that of a personal computer.
Korean Patent Application Publication No. 10-2010-0133245 discloses a method for controlling a mobile terminal for allowing two icons displayed on a touch screen to overlap while some areas thereof do not overlap and are exposed, and for allowing one of an upper icon or a lower icon to be selected according to touch pressure applied by a user to the overlapping area. However, in the method disclosed in Korean Patent Application Publication No. 10-2010-0133235, since one of the overlapping icons is required to be selected according to the touch pressure, such an icon selection method may cause inconvenience to the user.
Furthermore, although the functions of the mobile terminal extend with several functions added thereto, voice communication (or video communication) is still the main function. When a mobile terminal performs voice communication through a wireless communication network (e.g. CDMA network) provided by mobile service providers, the mobile terminal may carry burden of paying for call cost in proportion to call time. Regarding this, Internet-based free call services, such as Skype provided by Daesung holdings, Korea, or the international service Ofee, are widely used.
The foregoing services are mainly provided in a manner that wireless communication networks provided by mobile service providers are minimally used or Internet phone services are used in order to reduce call costs.
In many cases, customers want better call quality even if it requires paying more, but the above-described services or applications have limitations to satisfy such customer demands. Accordingly, a mobile terminal user requires: a communication service having excellent call quality for cost without depending only on exiting wireless communication networks provided by the mobile service providers; and a more convenient interface to use such communication services.